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What is an ecosystem?
The living things in a particular area and the nature of the physical environment
What is a habitat?
The places in which organisms live
What is a population?
All the organisms of one species in a habitat
What is a community?
All the populations of different species in a ecosystem
What are Abiotic Factors?
Non living, physical conditions in an ecosystem
What is an ecological niche?
The role of the organism in an ecosystem as defined by its food, competitors, predators ect.
Why is it essential that every species has its own ecological niche?
It prevents organisms of different species competing for exactly the same resources
What governs the ecological niche occupied by an organism?
Its adaptations to abiotic factors
Give two examples of how abiotic factors could affect the size of a population
The size of plant population in a pond may be limited by the availability of light at greater depths
The size of the population of bacterial cells may be limited due to a change in PH caused by products of their metabolism
What is interspecific competition?
Competition between members of different species
What is intraspecific competition?
Competition between members of the same species
What does competition ensure?
Only the fittest organisms survive long enough to reproduce (natural selection)
How is population controlled by predation?
If the number of prey increases them there will be more food for predators so their numbers will also increase.
The predators eat more prey so their population decreases, this reduces the availability of food for the predators and their numbers also decline after a period.
The extent of the fluctuation in numbers depends on the range of prey available to the predator
AQA BIOL4 Populations